Subdivide and separate face into different meshes
In Edit mode -> Select the face 
W -> Subdivde -> tool shelf T or F6 -> Number of Cuts (in your case 3)
With the subdivided faces selected -> Ctrl + E -> mark sharp
Add edge split modifier -> uncheck edge angle
In Object mode apply the edge split modifier
(optional) in Edit mode -> select the faces if not selected -> Ctrl + E -> clear sharp 
In Edit mode -> P -> separate by loose parts